Electric switch



2 Sheets-Sheet 1 Arron/ven Dec. 27, 1938. E.K. sAnLER ELECTRIC SWITCH Filed Nov. 4, 1935 E. K. SADLER ELECTRIC SWITCH Dec. 27, 193:5.y

Filed Nov. 4, 1935 2 SheetS-Sheet 2 Patentd Dec. 27, 1938 UNITED STATES PATENT OFFICE ELECTRIC SWITCH Application November 4, 1935, Serial No. 48,094

19 Claims.

My invention relates to circuit interrupters and more particularly to a switching mechanism particularly useful in breaking high-voltage circuits, though the principles and structures hereinafter described can also be used to advantage on lowvoltage circuits.

It is an object of the present invention to provide an improved structure for quickly and positively breaking an electric circuit.

Another object is to provide an improved switching system in which a blast or stream of dielectric medium is forced across a set of electric contacts during opening thereof to quickly quench the arc tending to form therebetween.

Possibly the best way of obtaining such a blast of dielectric medium is to utilize as an impelling force the expansion and gas generation occurring when another set of contacts is opened, and it is an object of the invention to open certain of` the sets of contacts slightly ahead of others to cause expansion and gas generation which cause movement of a stream of dielectric medium across other sets of contacts when these are opening.

Another feature and object of the invention is a novel arc-quenching tube means guiding this stream to a position across and beyond the subseouently-opening set of contacts.

The provision of a multiple-tube arc-quenching structure is another object of the invention. l A further object is to provide an arrangement of contacts and conductors setting up magnetic fields tending to extinguish the arc between separating contacts.

Still another object of the invention is to provide a plurality of switch elements submerged in an insulating medium communicating with novelly arranged storage chambers.

Another object is to position switch elements in novel relationship relative to a pair of spheres, ind preferably to position such switch elements in a tube of insulating material extending between two spheres. l

In the preferred embodiment the spheres may be hollow to function as the `storage chambers and the tube of insulating material may openly communicate with these chambers, the insulating medium at least partially filling the space defined by the tube and the storage chambers. The provision of such a structure is included among the objects of the invention.

Another object lies in the provision of a structure including an end supported tube means housing the contacts, and also a structure in which the operating mechanism for the switch contacts extends along this tube means.

The invention also provides a novel movable support means for a switch mechanism and a novel insulating structure for supporting the spheres, the provision of these structures being among the objects of this invention.

Still further objects will be apparent to those skilled in the art from the following description of one embodiment selected for illustrative purposes as best illustrating the features and principles of this invention.

Referring to the drawings:

Fig. 1 is a side view partially in section of one embodiment of the invention.

Fig. 2 is an enlarged sectional View of the sets of switch contacts utilized in the switch of. Fig. 1, and shown in the position they assume just after the instant of tripping of the circuit interrupter.

Fig. 3 is a diagrammatic view of the current paths in the switch shown in Fig. 1.

Fig. 4 is a sectional View taken on the line 4 4 of Fig. 1.

Referring particularly to Fig. 1, a foundation IU supports two columns of insulating material II l and I2 shown as comprising corrugated insulating bushings of cylindrical form to define chambers I3 and I4. I

The column or support I2 may be fixed to the foundation in any desired way, such as by bolts l5 extending through a flange I6 cemented or otherwise secured to the lower end of this column. The

' foundation Ill may be provided with a chamber I9 closed by any suitable means, such as a plate 20, and communicating with the chamber I4.

In smaller installations the column or support I I may be similarly secured to thr foundation IU, but in the larger installations it is often desirable to utilize an expansion-permitting means joining this column and the foundation. Various sliding or rolling systems may be used to permit slight horizontal movement of this column when expansion takes place. In the illustrated embodiment this means is disclosed as including rollers 2| rolling along the foundation I0 and being pressurally engaged by a plate 22 secured by a flange to the bottom of the column II. A pair of guide rails may be secured to the foundation to slidably engage the sides of the plate 22 to guide the eX- pansive movement, one of these guide rails being indicated by the numeral 23.

Suitably supported by the column I I is a structure forming an expansion chamber 24 in open communication with the chamber I3. Many advantages accrue from utilizing a hollow sphere 25 in this capacity and it is often very desirable to use this sphere as one terminal of the switching system. As best shown in Fig. 2, a ange 26 cementedio the top of thecolumn II may be used to secure the sphere 25 to this column.

Preierably this iiange engages an annular wall 21 of an indented portion 28 of the sphere 25, this indented portion being provided with a rounded shoulder 28 to prevent corona formation. Suitable cap screws secure the flange 26 to the sphere 25 and are threaded into openings extending only partially through the ange. A manhole 38 closed by a plate 3I permits access to the storage chamber 24 and has a terminal element 32 secured thereto for connection to a conductor 33 ci the circuit to be interrupted. A suitable vent 31 is provided at the upper portion of the sphere 25 and a means such as a p'an 38 is provided to prevent entry of water if the switching system is used outdoors.

A sphere 46 constructed similarly to the sphere 25 is supported by the column I2 and provides an expansion chamber 4I openly communicating with the chamber I4 and provides a terminal element 42 connected to a conductor 43 of the circuit to be interrupted. Vent means 4'4 and a manhole covered by a plate 45 are similarly provided.

The spheres 25 and 40 respectively provide indented portions 41 opposed relative to each other and formed similarly to the indented portion 28, previously described. A main tube 50 extends therebetween, carrying flanges 5I positionedin these indented portions and secured by cap screws 52 extending only partially through these flanges. This main tube is formed of insulating material and deiines a main chamber 53 communicating with the expansion chambers 24 and 4I Insulating medium, usually a liquid, such as dielectric or transformer oil, lls the main charber 53 and the chambers I3 and I4 and partially lls the expansion chambers to a level indicated by the numeral 55.

Plates of dielectric material 56 extend across the indented portions 41 and provide central openings 58, these plates being secured in place by the cap screws 52. Concentric annular channels 53, 68 and 6I are formed in each of these plates and an auxiliary tube of insulating material 63 extends between these plates with its ends in the outer annular channels 58. The auxiliary tube 63 is imperforate throughout its length and thus takes the radial pressure or strain exerted upon expansion of the dielectric medium due to heat or formation of gases when the circuit interrupter operates. It thus prevents tension strains in the main tube of insulating material 50. To better serve this function the auxiliary tube 63 is preferably of slightly smaller diameter than the tube 50 to dene an annular space 64 therebetween, small openings 65 being formed through the plates 56 to communicate between this annular space 64 and the expansion chambers.

In some instances it is desirable to utilize a baie tube 66, also formed of insulating material, its ends terminating in the annular channels 60 of the plates 56. An annular space 61 is defined between the tubes 63 and 66 and may conveniently house a part of the operating mechanism of the switch, as well as certain conductor means, as will be hereinafter described.

An arc-quenching tube means is provided within the bailie tube 66 and preferably includes two arc-quenching tubes 'I8 and 1I formed of insulating material. The ends of the outer, thicker, tube 18 extend into the channels 6I of the plates 56, a space 12 being provided between the baiile tube 66 and this arc-quenching tube. Openings 'I3 in the plates 56 communicate between this annular space 12 and the expansion chambers.

While the inner arc-quenching tube 1I may be similarly mounted between the plates, I prefer to center and mount this tube by radially-extending threaded pins or screws 14 extending inward from threaded passages of the tube 10. Projections 16 of these screws extend into correspondingly sized sockets oi the tube 1I. An annular space 18 is thus formed between the arcquenching tubes, this space being entirely open at its ends to allow a very tree communication to and from the expansion chambers. The outer ends of the inner arc-quenching tube 1I are similarly completely open to allow free communi` cation between a chamber 18 therein and these expansion chambers.

A series oi sets of contacts are provided as indicated by the numerals 80 to 88 inclusive, each set of contacts including aprimary contact and,

a secondary contact disposed opposite each other. The primary contacts are indicated by the numerals 80 to 88 inclusive, while the secondary contacts are indicated by the numerals 86" to 8B inclusive.

Each of the primary contacts 86 to 88' may be formed of a rod of conducting material, preferably circular in cross-sectional area, extending through openings of corresponding size in the tubes 66, 18, and 1I. If desired, these primary contacts may be suitably tipped with an arcresistant material such as Silver Elkonite as indicated in Figs. 2 and 4. These primary contacts may be xed to a rod of insulating material 80 by means of collars 8I. Any suitable means may be utilized for mounting the rod of insulating material 80 in the annular space 61. Fig. 2 discloses this rod as extending between the plates 56, being retained by nuts 82 threaded to the. ends of this rod and engaging these plates.

The secondary .contacts 80 to 88 may be similarly formed of rods of conducting material, thoughin some instances it is desirable to pro vide squared portions at the outer ends thereof. These secondary contacts extend into the chamber 18 in opposed relation to the primary contacts. They may be similarly tipped with arcresistant material, and movably extend through openings of corresponding size in the tubes 66 and 1I, these openings being only slightly larger than the secondary contacts topermit this movement. The secondary contacts also extend through the tube 18, and further journalling of these secondary contacts is provided by collars 98 threaded or otherwise retained in the arcquenching tube 1U. If desired, a resilient means may be provided acting to move each secondary contact either into or from engagement with the corresponding primary contact. The second expedient is preferable, a compression spring 88 being shown in Fig. 2 as extending between a bottom wall |00 of each collar 88 and a pin IDI carried by the corresponding secondary contact. A major portion of the spring 88 is thus positioned in a cavity of the collar S8 in each instance, such springs insuring very quick separation of the primary and secondary contacts when the circuit is being interrupted.

A suitable operating means is provided for mov` ing each of the secondary contacts into and from engagement with the primary contacts. This operating means is disclosed as including a rod |20, preferably formed of insulating material, extending through somewhat larger openings |2| in the plates 55 and being journalled in bearings |22, preferably oi the ball type, positioned in bearing caps |28 suitably secured to these plates. Open 'communication between the annular space 51 and the expansion chambers is thus provided through the enlarged openings |2| and the bear- .ings |22.` This operating mechanismalso includes a suitable linkage or other means `for opyeratively connecting the rod |20 to each of the secondary contacts 80" to 88" inclusive. Such\ a linkage is shown as including a series of collars |25 suitably secured to the rod |20 as by pins tacts 80" to 83 simultaneously disengage the corresponding primary contacts 80' to 88', the

pins |28 may extendthrough openings of corresponding size in the secondary contact, as shown, for instance in the secondary contact 82". In

.this instance, only suflcient play will be allowed to compensate for the slight arcuate movement of the pin |28 about the axis of the rod |29. The openings in the secondary contacts may be partly elongated in a horizontal direction to permit this action.

However, in the preferred embodiment of the invention I nd it preferable to open certain of the sets of contacts simultaneously and slightly ahead of the opening of other sets of contacts. In the embodiment shown the sets of contacts which should rst open .are the sets 8i, 8, and 8?. The'corresponding secondary contacts of these sets are thus pivoted to the pins |28 without excessive play being provided therebetween. `As to the remaining sets of contacts 80, 82, 83, 85, 85, and 08,' a resilient means is preferably associated with the linkage connecting the corresponding secondary contacts to the operating mechanism. While various resilient meansmay be utilized, Fig. 2 illustrates the pins |28 corresponding to these secondary contacts as extending through enlarged openings |36. 'I'hese openings are sufcientlyl large to retain contact elements |39 which are resiliently forced into engagement with the pins |28 by a compression spring |32. These openings |30 are also suillciently elongated in a horizontal direction to compensate for the slight amount oi arcuate movement of the pin |28 during rotation of the rod |20. Such a structure causes the -pin |28 to resiioiently engage the lower wall of the opening |30 until such time as the corresponding secondary contact engages the corresponding primary contact. Thereafter, a slight additional movement is permitted by compressing the spring 82.

The rod |20 extends rightward into the chamber 4| and. carries a collar |40I providing arms |4| between" which a pull rod |42 extends. A

-pin |42 carried by the arms |4| extends through this pull rod to pivotally connect the collar |40 and the pull rod |42. This pull rod |42 extends downward inthe chamber :I4 and may be journalled in a'hub'l45 of `a spider |46. When this f-pull rodis moved upward, the rod |20 is turned tobring the secondary contacts into engagement withthe primary contacts to close the circuit.

'connecting corresponding collars 9i.

ward, the secondary contacts move away from the primary contacts to interrupt the circuit.

Any suitable means, well known in the art, maybe provided for moving the pull rod |42 upward and downward. I have diagrammatically shown' this mechanism as including a closing solenoid |50, remotely energized, and providing a plunger operatively connected to the pull rod |42 by a toggle mechanism. This toggle mechanism is shown as including a pair of toggle arms |52 and |53, the arm |52 being connected to the pull rod |42 by a pin |54., A pin |55 pivotally connects the toggle arms, the toggle arm |53 being pivoted to the plunger |5| by a pin |56. The usual stop means is provided, diagrammatically shown as including al projection |58 on the toggle arm |52 and engaging a stop |59 on the toggle arm |53. When the toggle is closed, upward movement of the plunger |5| will close the switch. Suitable means is provided for breaking the toggle to trip the switch. In this capacity I have diagrammatically shown a trip coil |66, remotelyv energized, and so disposed that energization thereof will break the toggle, permitting the springs 99 .to quickly separate the contacts. 'Ihis trip coil may be mechanically connected to the toggle or may merely magnetically attract a portion of the toggle. mechanism in such a manner as to break the toggle when energized. Various closing and trip mechanisms are known in the art and may be used in conjunction with the present invention, it being ciear that li am not limited to the system diagrammatically shown.

The current ows from the conductor 32 through the sphere 25 and to the set of contacts 80 through a conductor |10 extending through an enlarged opening in the plate 56. From this point the current flows through the set of contacts 8G to the set of contacts 8| through a conductor |1t After traversing the set of contacts 8|, the current ows to the set of contacts 82 through a exible conthrough conductors of a flexible nature and nnm bered |12, |16, and |18, these conductors being suitably secured to the secondary contacts in position best shown in Flgs.,2 and 3. From the last set of contacts 88 the current flows through a conductor |19 to the sphere 40 and thence to the conductor 43 of the line. This sinuous or zig zag ow is particularly desirable in view of the magnetic blow-out effect thereby obtained. In the present invention the setsof contacts are disposed close enough to each other so that each set of contacts is under the influence of a magnetic 'eld set up by the ilow of current through the adjacent sets of contacts or through the conductors connecting the primary or secondary contacts. Thus,'when one set of contacts opens, thecurrentiiowng throughan adjacent set of contacts or through the yconductors connected thereto will have a magnetic blow-out effect tending to displace the arc resulting from separation of the ,contacts of the mst-mentioned set.

However, the most pronounced arc-quenching tendency arises from the setting up of a flow of dielectric liquid across the contacts of the sets which separate last; As previously mentioned, with the nine sets of contacts 80 to 88 inclusive illustrated. it is desirable to open the sets 8|, 84,

i, Conversely, when thepull rod |42 ismoved downyand 81 an instant ahead of the time that the other sets of contacts open. This time interval is preferably in the neighborhood of one-half cycle, though a larger or shorter time interval may be utilized if desired.

Considering, for instance, the action which takes place when the contacts 8|' and 8|" of the set of contacts 8| separate and move into the position shown in Fig. 2, it will be clear that a heavy arc will be set up through the oil therebetween. This arc tends to very suddenly increase the pressure in the vicinity of these primary and secondary contacts 8|' and 8|" due to at least two actions. In the first place, the formation of such an arc generates gas from the dielectric liquid. In the second place, such an arc very suddenly heats the adjacent dielectric liquid, causing very sudden expansion thereof. Both of these factors serve to suddenly and veryA materially increase the pressure adjacent the separating contacts.

In the present invention this very sudden increase in pressure in the confined space 19, defined by the inner tube 1|, causesl a sudden flow of dielectric liquid in opposite directions along the chamber 19 from the kvicinity of the set of contacts 8|. The leftward flow of dielectric liquid is indicated by arrows |80 and traverses the contacts of the set 80 in its flow toward the open end of the tube 1| and thence into the expansion chamber 24. The result is that at a later instant of time when the primary an'd secondary contacts and 80 are separating with a tendency to form an arc therebetween this arc will be blown out or extinguished by the leftward flow of highvelocity dielectric liquid moving as indicated by the arrows |80. This extlnguishment of the arc will occur at the first instant of zero potential following opening of the contacts of the set 80 or, in case of heavy current flow, at any point on the current wave.

Similarly, the rightward-flowing stream of dielectric iiquid moves from a position adjacent the set cf contacts 8|, as indicated by the arrows iGi, so as to traverse the contacts of the set 32 when these contacts open. In a similar manner, separation of the contacts 84 and 84" of the set Bil will set up a high-velocity leftward-flowing stream of dielectric liquid indicated by the arrows 82 and which traverses the contacts of the set 83 when these contacts separate. A rightward-flowing stream traversing the set 85 and indicated by the arrows i233 is also formed.

It will be -clear that the streams indicated by the arrows 38 and |82 meet in the space between the sets of contacts 82 and 83. This action forces the excess dielectric liquid radially outward through a passage means formed by openings |85 of the tube li. A portion of this outward-flow'- ing dielectric liquid moves along the annular space is and into the storage chambers, but a major portion thereof continues to new outward through a passage means termed by openings |81 through the arc-quenching tube lo. Entering the annular space 'J2 this outward-neiging dielectric liquid is deflected to move along the space i2 and through the openings 'i3 into the expansion chambers 213 and 4i.

Similar streams are formed from each side of the contacts or the set Si' when these contacts separate, thus providing streams of dielectric liquid which traverse the sets 36 33. Passage means 23S and im are formed through thetubes\ '5i and 28, as pr sly described.

The operating mechanism iis preferably so de signed that the secondary contacts 3y' to $8" are moved entirely from the chamber 1l and to such a position that the contacting surfaces thereof enter the annular space 1l, assuming a position, for instance, as indicated by dotted lines |90 applied to the set 80. I2 the arc is still persisting it will be clear that corresponding sidewisemoving streams will be formed in the annular space 18 which traverse the adjacent setslof contacts, as previously described. Such auxiliary streams are especially desirable at the particular instant that the contacting face of the secondary contact 80", for instance, just clears the outer peripheral surface of the arc-quenching tube.1|. At this instant, only a minute space will exist between this contacting surface and the peripheral surface so that a high-velocity stream sweeps across the contacting surface through this minute space at this instant..

Oneof the important features of the present invention is the confining of the streamscof dielectric liquid until they move beyond the adiacent contacts of the adjacent sets. The tube 1|, and in some instances the tube 10, performs this desirable result. For example, consider in Fig. 2 the dielectric stream indicated by the arrows Ill. It will be noticed that the tube 1| not only extends to the contacts I0 but also continues a substantial distance beyond the contacts before it dispersos into the reserve body of oil. By virtue of this arrangement. the arc cannot avoid the stream by merely looping outward.

Another feature of theninvention is that open paths are provided .for'the respective ilows o! dielectric liquid. The open-ended tube 1| is particularly important in this regard, as well as the openings |85 and |81 and the open-ended space i8. I' have found it very desirable to utilize two arc-quenching tubes 10 and 1| for several reasons. 0f primary importance is the function of these tubes in confining/ the high-pressure flows so as to reduce the radial pressures exerted on the other tubes of insulatingmaterial, and particularly the auxiliary tube 63 and the outertube 50. The very high pressures are thus confined by small and relatively thick-walled arc-quenching tubes disposed near the center vof the outer tube 50.

It is apparent that the employment of concentric tubes both provides for confining the central high pressure fluid streams and provides for directing two successive blasts against the arcs to be extinguished. In this latter aspect of my invention the radial disposition of the contacts is important. The retreating contacts draw the gas-generating arcs into the fresh body of oil in the annular space between the concentric tubes. Rapidity of operation is required, therefore the fact that the contacts are radially disposed is important, since the high pressure developed in the innermost tube acts against the ends of the contacts and speeds their retreat to the annular space.

. The invention is also novel in providing expansion chambers at each end of a switching arrangement to .receive any excess dielectric liquid caused by expansion or gas generation. These expansion chambers also permit the establishment of closed circulation paths for the dielectric liquid.

Another very important feature of the present invention is that the entire switching operation is effected within the outer tube 5U and in a zone of controlled flux distribution'. In this connection it will be clear that the spheres 25 and Il control the flux distribution along the length of the intervening tube means and'across the several sets of contacts, subnantially equalizing the potential across each set so that the entire potential is not placed across one or a few of these sets of contacts as is often'the case in' other types of high-tension switches. I believe it to be new to perform the switching operation between such spheres controlling the flux distribution across the individual sets of contacts. Similarly, to dispose in lineal relation all of the contacts performing the circuit-breaking' function gives better flux control and very emcient operation.

Certaindimensional factors are important if best results are to be obtained. Thus, considering the diameter of thel spheres 25 and lli as X, the distance Y indicated in Fig.- 1- should be equal to or less than X. Similarly, best results will be obtained if the distance between the vspheres and the foundation IU is equal to or less than the distance X, this dimension vbeing .indicated by the numeral Z in Fig. 1. However, the dimensions Y and Z`may be made larger if desired,A though this will often result information of corona discharges from the spheres.

- It will be clear that the teachings herein set forth are not limited to thervnumber of sets of Y contacts herein disclosed, this number being selected only for illustrative purposes. A smaller orlarger number of sets of contacts may be utilized without departing from the spirit of the invention, the number of sets of contacts being selected with reference to the desirable flows of dielectric liquid. In some instances, two sets of contacts will suil'ice, the flow of dielectric liquid being confined so as to traverse at least one of these sets, being generated by opening of the other set. Usually, however, it is desirable to utilize the two-direction ow, and in this instance it is desirable to utilize at least three sets of contacts.

Various modifications may be made in the invention without departing from the spiritl of the appended claims which I desire to be interpreted as broad as possible in view of the existing art.

I claim as my invention:

1. In combination in a circuit interrupter: an

arc-quenching tube means submerged in a dielectric medium and providing passage means including one or more ass es thro h which the dip ag ug communication with each other; anda body of electric` medium inside said tube may communicate with the dielectric medium exterior of said, tube; 'a set of laterally'disposed contacts in said tube to one side of said passage means; another set f laterally disposed contactsin said, tube to the other side of said passage means; means for opening vsaid sets of contacts; and means forcing streams of dielectric' mediurn along said tube means and respectively acrosssaid sets of contacts during opening thereof before reaching said passage means, each of said streams flowing in a direction toward said passage means whereby said streams flow toward each other and meet to force dielectric medium outward from the in terior of said arc-quenching tube means through said passage means.

2. A- combination as defined in claim 1 in which said last means includes two other sets of contact elements positioned in said tube means beyond the two previously named sets of contacts and being adapted when opened to force said dielectric medium away therefrom, thus forming said streams of dielectric medium moving toward each other along said tube means and thence through said passage means.

3. In combination ina cvircuitinterrupter: an

arc-uenching tube means open at. its ends and providing a passage means therethrough at a position between said open ends, said tube means being submerged in a dielectric medium to be end of said tube means; means for opening vsaid sets of contacts; and means for forcing oppositely-flowing streamsof said dielectric medium respectively across said sets of contacts during opening thereof, said means flowing one stream of dielectric medium in one direction toward and from said open end of said tube means and flowing 'nother stream of dielectric medium in an opposite direction toward and from said passage means.

4. In combination in a circuit interrupter: arequenching tube means; a plurality of primary contacts extending into said tube means and spaced from each other; a plurality of secondary contactsext'ending radially into said tube means to removably engage said 'primary contacts', each primary contact cooperating with its corresponding secondary contact to form a set oi contacts; conductor means outside said tube means for connecting said sets of contacts in series to form a zig-zag path for the/current owing through said sets of contacts connected in series; means connecting said sets of contacts connected in series to the circuit to be interrupted; and means for separating said primary and secondary conthrough said tubes and said annular space; sec-A ondary contact means extending radially through said tubes and said annular space and engageable' with said primary contact means inside said,

inner arc-quenching tube, the ends of said inner tube and of said annular space being in open dielectric liquid submerging said primary and secondary contact means.

s. A combination as dennen 1n claim s in which said dielectric liquid fills the space inside said inner tube and fills said annular space, and including passage means through said inner tube openly communicating with the dielectric liquid inside said inner tubel and in said annular space.

7. In combination in a circuit interrupter: a .plurality of tubes of insulating material submerged in a dielectric liquid; means retaining said tubes in concentric relationship and spaced from each other to provide a plurality of spaces lled with said dielectric liquid, said tubes providing a plurality of sets of openings aligned to form a plurality of contact receiving spaces; a

set of radially-extending contacts in each contact receiving space and providin engageablel contacts extending in opposite ends of said contact of contacts to interrupt said circuit.

8. In combination in a circuit interrupter:

means providing a container for retaining a body of dielectric liquid; an arc-quenching structure submerged in said dielectric liquid and formed of insulating material and providing an elongated arc-conning passage communicating at both ends with said dielectric liquid whereby said passage can receive and discharge dielectric liquid from and into saidA body of dielectric liquid through each end of said elongated passage;

three primary contacts providing contacting faces in said chamber; means electrically connecting the first of said primary contacts to one side of the circuit to `be interrupted; means for electrically connecting the second and third contacts together; three secondary contacts extending radially through said structure at positions re spectively opposite said primary contacts and movable into and from engagement with said contacting faces thereof; means for electrically connecting together the rst and second of said secondary contacts; means electrically connecting the third of said secondary contacts to the other side of said circuit tobe interrupted; and means for moving said secondary contacts from engagement with said primary contacts to form three substantially parallel arcs, the arc between the second of said contacts generating gas forcing streams of dielectric liquid in opposite directions therefrom across the ilrst and third contacts, said streams being confined by said arcquenching structure to ow in said opposite directions and thus sweep across the resulting arcs between said iirstcontacts and said third contacts while flowing in said opposite directions.

9. A combination as dened in claim 8 in which said primary .contacts .also extend radially through said structure, and in winch said means for electrically connecting said second and third ci said primary contactsv and said means for electrically connecting` said first and secnd of said secondary contacts comprises conductor means outside of said arc-quenching structure and thus 'spaced from said streams, thereby -producing a zig-zag current path. partially inside and partially outside said elongated chamber, said first, second and third contacts being suii'lc'iently close ytogether in said elongated passage that the magnetic action of each arc inuences and tends to deform the other arcs.

l0. In combination in a circuit interrupter:

an arc-quenching structure providing an clongated passage filled with dielectric liquid; a first set of engageable contacts extending radially through said structure and into said elongated passage; a second set of engageable contacts extending radially through said structure and into said elongated passage; an intermediate set of contacts between said first and second sets and extending radially through said structure intosaid elongated passage; and means for opening all ci' said sets of contacts, said means opening said intermediate set of contacts slightly ahead of the opening of said first and second sets of contacts whereby the sudden volumetric expansion adjacent said intermediate set of contacts forces dielectric medium from the vicinity thereor in oppositely-moving streams which respectivelytraverse said first and second sets of contacts during the delayed opening thereof.

11. in combination in a circuit interrupter: a

'. tube of insulating material; a plurality of sets of contacts in said tube connected with the circuit tcbe interrupted; and members of conducting material at the opposite ends of the tube, saidV members having spherical faces disposedtowards each other, saidsphericalfaces extending laterally of the tube at least 90" from the axis of the tube to substantially equalize the potential across each of said sets of contacts when the circuit is being interrupted.

12. A combination as deilned in claim l1 in which lthe sets of contacts are series-connected and in series with said members of conducting material in the circuit to be interrupted.

13. In combination in a circuit interrupter: a substantially horizontal tube of insulating material; walls forming an expansion chamber at each end oi.' said tube, said expansion chambers and the interior of said tube being in open communication and containing a dielectric liquid, said dielectric liquid only partly filling said. expansion chambers; a plurality of sets o1' contacts in said tube submerged in said dielectric liquid. said sets of contacts being connected in the circult to be interrupted; and means for operating said sets of contacts to interrupt said circuit, the generation of gas by arcs formed in the operation of the contacts forcing dielectric liquid along said tube towards each of said'expansion chambers, said walls-'of the expansion chamber adjacent said tube being of conducting material in series with said sets of contacts and being concave and sloping outward away from the ends of the tube to serve as means for tending to equalize the potential across each set of contacts when the circuit is being interrupted.

14, In combination in a circuit interrupter: a pair of spaced spheres of conducting material; a tube of insulating material interconnecting said spheres; a plurality of sets of contacts within said tube, both the contacts and said spheres being in the circuit to be interrupted, whereby said spheres tend to equalize the potential across the intermediate sets of contacts; means of insulating material supporting each of said spheres, at least one of said supports being hollow; and means in said hollow support operatively connected to said sets of contacts for opening same to interrupt said circuit.

l5. In combination in a circuit interrupter: a

Apair of spaced spheres of, conducting material electrically connected to the circuit to be interrupted; an outer tube of insulating material interconnecting said spheres; an inner arc-quenching tube means disposed in said outer tube and defining therewith an annular space; a plurality of sets of contacts in said inner tube means, said contacts being electrically connected in series with said spheres whereby said spheres tend to equalize the potential across said sets of contacts when the circuit is being interrupted; and mechanism in said annular space for operating said contacts.

16. In combination in a circuit interrupter: a pair of spaced hollow members of conducting material having oppositely disposed openings; tube means formed of insulating material interconnecting said openings; a plurality of sets of contacts in said tube means, said sets of contacts and said hollow members being connected in series in the circuit to be interrupted, said hollow membershaving convex faces disposed towards each other, thereby serving to distribute potential across the plurality of sets of contacts; and mechanism for operating said sets of contacts.

17. In combination in a circuit interrupter: a spaced pair of spheres of hollow conducting material having oppositely disposed openings; tube means formed of insulating material interconnecting said openings; a plurality of sets of contacts in said tubemeans, said sets ofecontacts and said spheres being connected in series in the circuit to be interrupted. said spheres serving to .dlltribute potential across 'the plurality o! sets oi' contacts; andmechanism for operating'said sets of contacts.

18. In combination in a circuit breaker: means providing a container for retaining a body of dielectric liquid; an arc-quenching structure submerged in said dielectric liquid and formed of insulating material providing adjacent arc-conmiing passages communicating with said dielectric liquid whereby said passages can receive and discharge dielectric liquid from and into said body of dielectric liquid; primary contacts extending into one of said passages; complementary secondary contacts movably extending laterally into said passage from a second adjacent passage whereby pressure generated in the ilrst passage will tend tofmove said secondary contacts into said second passage; means electrically connecting said contacts with the circuit to be interrupted; and means to move said secondary contacts away from said primary contacts, thereby drawing arcs in said first passage and generating a blast of'dielectric therein directed against one ot said arcs, said means being adaptedto move said secondary contacts rapidly into said second passage, thereby drawing said arcs into fresh dielectric liquid and generating a second successive blast directed against said arc through said second passage.

19. In combinationin a circuitbreaker: means providing la container for retaining a body of dielectric liquid; an arc-quenching structure submerged in s aid 'dielectric liquid and -formed of insulating material providing adjacent elongated arc-confining passages opening at their ends into said dielectric liquid whereby liquidl can enter said l lpassages from said body of liquidI and whereby blasts of dielectric liquid may be delivered through said passages into said body, there being contactreceiving apertures in the walls of jsaid passages; a set of contacts extending through some of said apertures and vmeeting in one of"said passages; means to separate said contacts thereby to form a generating arc for producing ablast through said passage and out the open end thereof, said means drawing the arc through one of said apertures into the adjacent passage to produce a second blast therethrough; and a second set of contacts extending through other of said apertures to meet in said ilrst passage. said second set o! contacts being operated by said separating means whereby an arc to` be interrupted is drawn from the iirst passage into the second passage across the paths of said blasts, said passages extending substantially beyond said second s'et of contacts whereby said blasts may eiiect said second arc when it is looped outward from its contacts.

ERNEST K. SADLIR.. 

